Trunnion Corrosion in Total Hip Arthroplasty-Basic Concepts.

There has been increased interest in the role of corrosion in early implant failures and adverse local tissue reaction in total hip arthroplasty. We review the relationship between the different types of corrosion in orthopaedic surgery including uniform, pitting, crevice, and fretting or mechanically assisted crevice corrosion (MACC). Passive layer dynamics serves a critical role in each of these processes. The femoral head-neck trunnion creates an optimal environment for corrosion to occur because of the limited fluid diffusion, acidic environment, and increased bending moment.